and this settings are the same on both servers:
- magic_quotes
- open_basedir (different path)
- register_globals

in /var/log/httpd/error.log

Code:

....[error] an unknown filter was not added: PHP

and when i look in popup windows source code:
in old (working server) i see: <a href="javascript: self.close();"><img src="images/image.jpg" border=0></a>
in new (isp config) i see: <a href="javascript: self.close();"><img src="images/" border=0></a>